1. Field of the Invention
The present invention relates to a method of managing a mobile multicast key using a foreign group key. More specifically, the present invention relates to a method of managing a mobile multicast key using a foreign group key for secure communication between a mobile terminal and a secure relay server in the region where microwaves from plural access points overlap.
2. Background of the Related Art
Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in this field.
Multicast is a method of simultaneously forwarding data such as a video or voice to more than two receivers in a wired or wireless network. Multicast is opposite of unicast, in which data are transmitted to a single specific receiver. Multicast is generally used to provide multimedia stream services in realtime for systems such as internet protocol-television (IP-TV) or video conference system. And such conventional multicast has disadvantages in that even a brief delay or packet loss can cause image-pausing or any other problems in providing consistent services.
Mobile multicast technology enables a multicast node to communicate with the other multicast nodes in the network when the multicast node moves and changes its access point in the network. The technology can provide a stream to multiple receivers simultaneously and block redundant transmission of data, and thus prevent wasting bandwidth and reduce transmission overhead. These are the advantages of mobile multicast technology over a unicast-based network. In other word, mobile multicast technology combines mobility with multicast technology, one of the key next-generation technologies.
However, mobile multicast requires solutions to security threats resulting from mobility as well as security threats which have existed in a conventional wired network. As examples of the security threats in mobile multicast, a normal user fails to receive services, due to a server masquerading as a normal server or due to a malicious mobile node transmitting a fake join message or leave message. To solve such security threats, technologies for user authentication and encryption which can support mobility are required.
As mentioned above, multicast has a difficulty in providing consistent services because of a brief delay or packet loss. And a delay becomes a bigger problem in mobile multicast since mobile multicast requires changes of secure relay servers.
In mobile multicast communication, a user is provided with services from access points, moving from one cell to the other. Accordingly, there are needs for user authentication for authenticating a user and updating a group key when he or she moves, and key distribution protocols for sharing a group key. When designing mobile multicast security, one must consider the characteristics of a mobile terminal such as computing power and batteries and so on. In addition, mobile multicast security must be designed in the respects of security, appropriateness and optimality. Security is for showing if a protocol which is made for mobile multicast security is secure, appropriateness for showing if the protocol satisfies the requirements for wireless environment, and optimality for showing if the protocol is superior and effective.
When providing services for a user of a mobile terminal, access points are required to first identify the mobile terminal and securely distribute a group key, which is used to protect multicast data. Accordingly, a method for identification and a protocol for distributing a group key are required to resolve security issues of mobile multicast service.